Liquid type vibration damper



Nov. '12, 194@r A. M. RocKwELl. 2,411,000 I I LIQUD vMPE nannten DAMPER f AFiled laren 3o.' 1944 Bwfm ` ATTORNEY LIQ TYPE RATIQN D i Albert lli. Rockwell, Glastonbury, Conn., assigner to United Aircraft Corporation, Conn., a corporation of Delaware East Hartford,

Application March 30, 1944, Serial No. 528,707 l i 2 Claims. (Cl. 74-604) 'I'his invention relates to vibration dampers and particularly to a combined torsional and translational or axial vibration damper of theliquid pendulum type. i

The invention is shown, in the embodiment selected for illustration, as applied to the crankshaft of an aircraft engine and is housed within one or more of the counterbalances therefor, there preferably being a plurality of containers forming dampers in each counterbalance and each container having therein a plurality of small Each of the containers I2 is provided with the mercury pockets or receptacles it and each may be curved as shown to fit a portion ci the outer openings forming pockets partially filled with a heavy liquid such as mercury.

An object of the invention is to provide a vibration damping means for crank-shafts'and the like in which the liquid, preferably mercury, is retained within a container and being sealed in a manner to prevent the pressure of the liquid, due to centrifugal force, from being applied against any of the solderedor welded Joints of the containers.

Another object of the invention is to enclose the mercury or other liquid holding containers within recesses within Yopposed counterweight members secured to the crankshaft on opposite sides of the crank cheeks.

Other objects and advantages will Ibe apparent from the specification and claims, and from the I drawing which illustrates what is now considered to be a preferred embodiment of the invention.

In the drawing: Fig. 1 is a side elevation of a crankshaft showperiphery ofthe counterweight il against which the containers I2 may be mounted. Each pocket or receptacle I3 extends transversely through its` container i2 and each pocket is partially iilled with liquid It such as mercury. To enclose these containers i2, Aa cap member i5y fitting their outer periphery, the sides and ends of the containers I2 is welded thereto throughout the 'edges of the cap member I5. As shown in Fig.,2, the edge of the cap member I'5 Welded to 'the containers t2 ing a preferred form of the invention, parts beingA shown in section on the plane of line l-l in Fig. 2;

Fig. 2 is a transverse sectional view on an enlarged scale and taken on the plane of line 2 in Fig. 1, and

Fig. 3 is a transverse sectional view taken on the planes of broken line 3--3 of Fig. 1.

In a preferred form the invention may includev Y counterweight portion il are secured a group of y \three similar containers i2 each container having a plurality of cylindrical compartments i3 partiallyglled with a heavy liquid it such as mercury.

extends along its inner arcuate surface so that during rotation centrifugal :torce will not serveto bring the liquid intov contact` with the. "weld or other form of joint IB. lThe inner arcuate surn faces of the containers i2 are provided with a single opening I6, by means of which liquid may be admitted to the individual receptacles. After `filling each receptacleto the desired level or with the required amount of liquid, this opening may be closed by a plug filling the opening l5, the outer end of which may beA welded to the conu tainer l2 to retain it in liquid tight relation thereto.

As shown most clearly in Fig. 2, the containers i2 for the pockets i3 are fitted into recesses milled or otherwise formed in the cap member l5, there being as shown, th'ree aligned recesses in the cap member i5 for these containers.

' Each of the pockets i3 for the liquid it may be divided into compartments by separating dia= phragms Il held spaced apart by being tted into milled grooves formed in the Walls of the pockets. To permit passage of liquid from one portion to another of the pockets i3, small openings 2l 'through the diaphragms Il may be provided. Also, to permit iiuid to pass fromV one pocket to another, slight openings may be formed as indicated at 22 between the side Walls of the con'l tainers and the cap member.

To retain the containers l2 and the cap member i5 in position, counterweight cheeks or closing members I9 recessed to receive the containers and .cap member may be bolted together on opposite sides of the crank cheek l I. These cheeks or closing members I9 may .be held in position by through bolts or rivets 2li extending transversely through the opposed closingA members I9 and through a portion of the crankshaft counter- Weight II. As shown in Fig. 1, there are three similar container members I2 placed end to end and -enclosed by a single cap member li' so that in eect there is a continuous series of liquid containing pockets I3 from one end surface of the crank cheek to the other. The pockets il for the liquid are arranged with their axes parallel to each other and parallel to the axis of rotation of the crankshaft. All of the pockets I3. therefore, form an arcuate series concentric with the axis of rotation of the crankshaft.

In operation fluctuations in the instantaneous speeds of the crankshaft I0, due to intermittent power impulses, will cause the fluid within each pocket or receptacle I3 to move forward or backward, also axial 'or translatory vibrations of the crankshaft will cause movement of the mercuryin the direction lengthwise of the receptacles or pockets I3. This action of the mercury serves to vary the inertia of the rotating mass and effects a damping of these torsional and axial vibrations.

In operation also the construction provides a large number of spaced pockets within which the liquid can ilow to uniformly tlll all pockets to an equal degree, and as the weld between the containers and their cap member is on the inner I trated and described, butv may be used in other- Ways without departure from the spirit of the invention as dened. by the following claims.

4` I claim: 1. A vibration damper of the liquid pendulum type comprising, a rotatable member, a container mounted thereon having a plurality of pockets,

container in fixed position to said rotatable' member.

'2. A vibration damper of the liquid pendulum typecomprising, a rotatable member, a container mounted thereon having a series of parallelly disposed pockets, a liquid partially filling each of said pockets, means to restrict but not prevent liquid ilowing from one pocket to another, said container having a lling opening therefor extending from the inner surface of saidcontainer,

a plug sealing said opening, a cap member secured to and enclosing the outer and side portions of said container for retaining said liquid within said pockets and retaining said pockets in an arcuate series, said container and cap member being permanently secured together along the periphery of said cap-member, and means to secure said container in fixed position to said rotatable member. l

ALBERT M. 

